Abstract: An improved plunger lift mechanism comprises an internal hollow body having bypass orifices that, when exposed, allow fluid to pass through during plunger descent in a downhole tube to the bottom of a production well. A slidable sleeve slides along the hollow body to close the orifices, causing the plunger to rise and carry accumulated fluid to the well surface. In addition, the present apparatus comprises surface interfaces between a slidable sleeve and a mandrel to minimize a probability of mandrel and sleeve separation during the plunger's ascent phase and a risk of plunger stall. By integrating a plunger lift having a slidable sleeve with closer limits between the slidable sleeve and an internal hollow body, and a wider plunger surface area, the present apparatus can minimize radial movement which can occur during plunger drop and when impact occurs.

Abstract: A downhole plunger for a gas/oil well has an automatic type of brake to reduce its travel rate as it approaches the bottom or top of the well, and to open and close apertures without the physical impact of mechanical valve by-pass plungers. Normally open fluid pass-through corridors in the plunger are shut when the higher temperatures downhole activate a thermal actuator. When the valve seat is moved to the closed position, the fluids cannot pass through the normally open corridors inside the plunger. This resultant increase in fluid resistance through or around the plunger slows the plunger down from a usual fall rate of about thirty miles per hour. When the plunger approaches the top of a well the thermal actuator partially opens to slow it down. An expanding pad version is shown too, as is a combination plunger with a data logger and a thermal activated brake.

Abstract: A downhole plunger for oil and gas wells is fitted with an electronic ambient environmental sensor via a cargo bay. The sensor is preferably a downhole time, temperature, pressure and flow sensor. The sensor has a measured data memory. When the plunger is retrieved from a well, the sensor is removed and connected to a computer for data display and processing. A data logger canister can be affixed to the top, the bottom, or one on the top and one on the bottom, of a plunger. An empty cargo bay can be a fluid sampler. Other items insertable in the cargo bay include corrosion coupons.